Designing and Modeling HVAC Systems with SystemOutliner Webinar (text version)

This webinar introduced SystemOutliner, a new software application developed at the National Renewable Energy Laboratory (NREL) to facilitate the design and simulation of HVAC Systems using EnergyPlus and OpenStudio. The key user features of SystemOutliner were demonstrated and discussed, including the ability to assemble custom HVAC systems through a drag and drop interface and rapidly model common HVAC system types using built-in templates.

Below is the text version of "Designing and Modeling HVAC Systems with SystemOutliner," originally presented on December 7, 2011. In addition to this text version of the audio, you can view the presentation slides and a recording of the webinar (WMV 18 MB).

Welcome, and thank you for standing by. At this time all participants are on a listen-only mode. I would like to inform all parties this call is being recorded. If you have any objections you may disconnect at this time. I know would like to turn the call over to Michelle Resnick, you may begin ma'am.

Michelle Resnick:
Thank you Lori. My name is Michelle Resnick and I'd like to welcome you to today's webinar title Designing and Modeling HVAC Systems with SystemOutliner. This webinar is presented by the Commercial Building Energy Alliances Program at the U.S. Depart of Energy.

We're excited to have with us today an expert who helped develop this software application. But before we start I have some house keeping items to cover. As Lori mentioned, everyone on the line today is in listen-only mode. We will have a Q&A session at the end of the presentation. You can submit your questions electronically throughout the webinar using the Live Meeting window.

To submit a question click on the Q&A link at the top bar of your screen, type the question in the box and click 'ask.' Please be sure to click 'ask' and not the symbol of the raised hand. Our speaker will address as many questions as time allows after the presentation.

Today's speaker is Kyle Benne from the National Renewable Energy Laboratory. Kyle is one of the principle developers on the OpenStudio Project and specializes in the SystemOutline application.

Another member of OpenStudio development team, David Gold-Wasser will be on hand to help answer questions during the Q&A session at the end.

Today our speaker will present an overview of the user features of SystemOutliner including the ability to assemble custom HVAC systems through drag and drop interface. He will also download the tool and discuss future development plans. And with that, I'll turn the presentation over to Kyle.

Kyle Benne:
All right, well, thank you Michelle. I'm going to start off today by showing you a few slides just to kind of orient you to what I'm going to talk about, but the majority of the presentation today is going to be a software demo.

So with that, let me start by giving you a little bit of background about the OpenStudio project. Some of you might already know what OpenStudio is about and some of you might not.

OpenStudio, from a user's point of view, is mostly known for its Sketch-up plug-in. So the sketch up plug in allows you to draw geometry in a relatively intuitive CAD environment and then create an energy simulation using Energy Plus with that plug-in.

But along the way we started to think, "Wow that's really nice to do energy modeling and to draw the architecture of the building." So we started to ask ourselves, as the slide is showing you, something's missing in this thing. We realized that OpenStudio does a good job on part of the model but that kind of leaves users out there hanging on the HVAC part of things.

So SystemOutliner of the application was started to compliment OpenStudio the Sketch-up plug-in to cover that other part of the model, particularly the HVAC.

So just a little bit of overview about my demos today and what I'm going to talk about. I'm going to kind of break things into four demonstrations; four live demos. The first one's going to be an end-to-end demo, I'm going to start on the Sketch-up plug-in and draw some very simple geometry and then go to the SystemOutliner application and add HVAC using a template.

From there I'll actually run a simulation and show you a process starting from nothing all the way to end-results from the EnergyPlus simulation.

Then there's going to be another demo on – going back in the SystemOutliner specifically talking about creating custom HVAC's. So in that one, instead of using templates I'm going to use a drag and drop interface to show you how to make your own HVAC systems.

And in another demo I'm going to show you how you can import existing IDF's in case you're already an EnergyPlus modeler and you've got some IDF's and you want to use OpenStudio with those, I'll show you how you can import them into the SystemOutliner.

Then the final demo is going to be maybe a little bit more technical but it will be talking about the scripting interface that is part of the OpenStudio project. So if you're a coder-type person and you want to automate your workflows or something like that, this part of the demo might be interesting to you.

Then we'll pop back over to some slides and I will talk about future plans and talk about where we want to add features and kind of acknowledge places where we have more work to do. And then finally there will be some time for Q&A at the end.

So, like I just said, this first demonstration is going to be an end-to-end demo using HVAC templates. And my hope is that this shows you how you can very quickly start from nothing and end up with a full HVAC and architectural energy model of your building.

And with that I'm going to switch over and show you all my desktop. Everybody should be seeing my desktop now. And I'm going to start by launching the Google Sketch-up application. During these stages I'll try to move relatively slowly and not adjust the camera angle because I recognize that you guys have a little bit of lag in seeing what I'm seeing, so just bear with me while I kind of get things set up.

The first thing that you're going to do if you're trying to model a building in OpenStudio is usually start from a template. The way you do that is by clicking on this icon up here. And then from there you can choose from some of our pre-populated templates. These are nice because they give you a starting point for doing the model, it's all import instructions and schedules and things for you automatically.

So in this case I'm going to show you how to make something that closely resembles a medium office building, so I'll start with that template. And then again I'm going to orbit around a little bit to set the camera angle. And then I'm going to draw a footprint of the building that I have in mind.

So I'm going to say, for my example, the building is 100 feet by 50 feet in footprint. And then for the example I'm going to make this a core and perimeter model. So what I just did is I made a basic footprint of the building and now I'm going to extrude that up to create what OpenStudio knows as 'of spaces.' So, how I do that is I select what I just drew and then I click on this icon up here 'create spaces from diagram.'

In this case I'm planning to make a building that is one floor and the height of the floor is going to be ten feet. So at this point what I have is known as – each one of these boxes in my building is an OpenStudio space. OpenStudio spaces are part of the model that captures geometry and also the part that the internal load and the people and things like that are applied to.

But OpenStudio has another concept known as 'the thermal zone.' If you're an EnergyPlus modeler you might already know what a thermal zone is, but in OpenStudio modeler these are two separate concepts. These are kind of handy. A space can reference at most one thermal zone; it can point to, at most, one thermal zone. And multiple spaces can point to the same thermal zone.

When we go to make an EnergyPlus simulation then those spaces get aggregated together into one thermal zone that EnergyPlus understands.

So to create those thermal zones I'm just going to make each space in my model – the five that I have here in my core perimeter model have a corresponding thermal zone that I'll then later connect my HVAC system up to. But I do this with a script up here called 'assign unique zones to untagged spaces.'

And with that I have one space and one thermal zone corresponding to each other. I'm going to take a couple more steps and then we're going exit the plug-in and focus in on adding HVAC systems to this five-zone model.

The first thing I need to do is do surface matching. And so this runs an algorithm that applies to proper construction and the proper boundary conditions to my spaces that are adjacent to each other and that are exposed to the outside. So OpenStudio has an algorithm that does this for you automatically.

And then the final step that I'm going to do inside of the plug-in is I'm going to add thermostats to each one of my thermal zones. So, again I select all of the spaces and I go up here to this icon and set attributes for the selected spaces.

And down here I set parent thermal zones thermostat. So for each one of these spaces that now has a thermal zone attached to it I select the thermostat that I want applied. And in this case I'm pulling in one that was provided to me by the template.

Now at the point that's the entire workflow from Sketch-up plug-ins point of view. I've defined architecturally the model so I'm going to save it.

And with that I'm going to switch over to SystemOutliner. This is the startup screen for SystemOutliner. In this case I don't want to start a new model; I want to open an existing one, the one that I just made.

So I go here and select that model. And now we'll see the main interface to SystemOutliner. Currently there are three tabs that make up SystemOutliner and the three tabs relate to the main portions of the OpenStudio model that relate to HVAC.

The first one is a schedules interface. Schedules, it turns out, are used widely throughout the HVAC system so it's important to be able to see the schedules. One thing we've done here is that we don't have a full-featured scheduled interface; rather we're showing you the schedules that already exist in the model and allow you to import other existing ones from an IDF file.

The next tab is a thermal zone tab and this shows you the part of the geometry that the HVAC system is going to attach to. So in this case we have tabs for every one of the thermal zones that we added over in the plug-in. And we also have information about the thermostats and the types of HVAC equipment that's attached to it.

In this case we don't yet have any HVAC systems but we do have thermostats down here. The final tab – and this is where most of the SystemOutliner functionality comes into play is the last one. And you can think of this as kind of like the loop view or the system's view.

In OpenStudio's EnergyPlus terminology we think of these things as loops. So in this case I want to add one of the templates, which I can go to from the library on the right-hand side to add HVAC's to this model.

In this case the library has templates that are loosely correlated to ASHRAE's appendix-G system types. So for example 'package terminal air conditioner' roughly represents System Type 1, 'package terminal heat pump' System Type 2 and so on. So we've added templates for all ten of the appendix-G system types.

In this case I'm going to go down here and grab System Type 7, 'package group set VAV with a reheat' in appendix-G terminology.

And when I add that to the model it comes hooked up with everything basically ready to go with the exception of the zones that we're going to apply to this system type.

So what you're looking at here is a representation of the HVAC system. And in OpenStudio those come in a supply side represented by this half, and a demand side represented by the half over here. And in fact that is similar to how EnergyPlus views the HVAC system too.

In the components that we have on that are an outdoor air system with an outdoor air mixer represented by this box, a water-cooling coil, a water-heating coil, a fan and an air terminal that on the demand side will supply a zone. In this case it's System Type 7 so it's a VAV with reheat.

Now the water coils are supplied by plant loops, so we hyper – we have an interface that lets you hyperlink to the plant's loop to each one of the water coils. You can click here and you'll be hyperlinked over to the chilled water plant. So what it is showing you is that the chilled water coil is a supply component on this air loop and then we hyperlink and we see that demand component on the chilled water plant. The same thing with the hot water coil, we can hyperlink over and we see the supply equipment on the hot water plant.

Each one of the components is inspectable. So for example, if I click on the fan you can inspect the properties of that fan, changes, efficiency and things like that.

And if you do that for a water coil it will even show you what plant this is connected to and you can make changes. I will come to this when I build up a system piece by piece and show you how that works in a little more detail.

So at this point to make a working model the only thing I have to do is click on the zone splitter – or the zone mixer – and start adding thermal zones that I want to attach to the system. So I'm going to grab them all and I'm going to attach them like that.

Now at this point the HVAC system is complete; the template provided most of the work for us so all I have to do is save. And we'll notice that if we toggle back over to the Sketch-up plug-in it's recognized that we've changed that model that we were working on over in Sketch-up and asks us if we want to reload it; so I say 'yes' and it will do that.

And one of the reasons that I came back over to the plug-in is that we can actually run the model and I can show that we actually created something that's workable and that we can actually get results for. And the way we do that is by clicking on the 'run simulation' button up here.

A couple of housekeeping things; I request that I want zone sizing and I specify a location and design days for the simulation to run.

So with those changes I'll go ahead and apply them and I'll click 'run' and the software will start running an EnergyPlus simulation for us. It will take about a minute to run this particular model so I'm going to go over and do the next portions of my demo and then we'll come back to this and I'll show you the results that we had from the simulation.

Now if I switch back to our slides for a moment I just want to reorient you to where we're at. So in the next portion I'm going to go back to SystemOutliner and rather than start from the plug-in I'm going to show you a workflow where you can actually start in SystemOutliner and add your thermal zones directly inside of SystemOutliner and then attach HVAC systems to the thermal zones that you've created there.

So for that I'm going to create a new model from scratch this time. The SystemOutliner comes pre-populated with the schedules that concern HVAC, so in this case I'm going to add a schedule set that's appropriate for a medium office again. And then I'm going to add a handful of thermal zones.

And on that thermal zone I'm going to turn on thermostat, I'm going to apply the schedule. And now I'm going to start building up an HVAC system piece by piece. So instead of selecting from one of the templates I'm going to go down to the bottom here and add an empty air loop. And then I'm also going to add an empty plant loop.

In this case, I'm going to show you how to do something that you couldn't do with a template and that is make a dedicated outdoor air system. So it will look a little bit like System Type 7 but it will have some subtle changes to it, which is why we need to build it up custom.

So I'm going to start by adding the supply components to the air loop. So, like similar to System 7, I'll add a cooling coil, I'll add a heating coil, I'm going to add an outdoor air system. You don't have to mess with node connections or anything like that. Basically you just grab a component from over here in the library and you drop them on node and the OpenStudio model takes care of the complicated connection business. I think this makes it quite a bit easier to manage EnergyPlus HVAC systems.

One more piece we need to fan, so I'll drop that in there. That's the basic outline of the components that I want on my air system. Now I'm going to switch over to one of my plants and I'm going to create a chilled-water plant. I'm going to name it that way. And I'm going to add supply equipment to the chilled-water plants; in this case a pump and a chiller. And I'm going to go to plant loop – the other plant loop – I'll call that the hot-water plant – and I'll add the boiler and the pump to that one.

One last step that I almost forgot; since we're building the system up from scratch we have to add control points. So to do that I go to 'set point managers' and I apply the control that I want to the nodes. In this case I want to apply a hot water set point to the supply outlet node of my hot-water plant. And on the chilled-water plant I'm going to do the same, I'm going to add 'chilled-water set point manager.'

If you're familiar with EnergyPlus these are the EnergyPlus mechanisms to provide control to the components.

Now, back over in the air loop I need to connect the water coils up to that plant loop. So I click on them and go over to the inspector, and I can then select which plant loop I want to connect the coil to. So in this case I connect to the chilled-water plants, you can hyperlink over there and you can see that it added it on the demand side of the plant. We'll do the same thing for the hot water coil.

Then I'm going to add set-point managers to the air loop so that it is controlled properly. In this case I'm targeting a system that's like a dedicated outdoor air system. So I'm going to apply a set-point manager that provides a constant supply air temperature with a set-point manager that has a deck temperature.

You can control what the supplier temperature is by the schedule that you select associated with the set-point manager.

And I'm going to add some more control points for the various coils upstream of the fan. This set-point manager that I'm dropping in here accounts for the fan energy introduced down here.

You might go through the options that are in the HVAC library and you'll see that one of the things that we've pre-populated is an evaporative cooler, so often times you'll find this kind of component on a dedicated outdoor air system. And you can drag and drop these components the same way.

If this is a 100 percent outdoor air system – from a modeling point of view it doesn't really matter if I drop it on the outdoor air system here or if I drop it here; either one of those would be an appropriate modeling choice. So the point here is that SystemOutliner is flexible to let you customize how you arrange your HVAC components.

And the final step is that I'm going to add the thermal zones. And here is an opportunity to show you some of the intelligence that's built into the OpenStudio model, some things that save you a whole lot of work if you're doing this in EnergyPlus directly.

So one thing I can do is drop an air terminal of my choosing for one of the zones. And I could go through the process of adding that same air terminal to each one of the zones, but if you've already got a zone hooked up to an air terminal when you add new ones the SystemOutliner will clone that air terminal so you'll only have to add it once and then select the zones that you want to apply to the loop.

And all of the air terminals do not have to match. So, it's uncommon, but if you wanted to add a different kind of air terminal you could do that as well. You could grab a different air terminal from the library and mix and match them like that. In this case I want them all to be the same.

So that's one way of doing HVAC in OpenStudio and inside of EnergyPlus. That is you use these air loops and plant loops to build up systems.

Another way of doing HVAC in EnergyPlus and OpenStudio is with the so-called zone equipment. And these pieces of HVAC equipment are more or less self-contained and they apply to one thermal zone exclusively. And the interface in SystemOutliner to do that is through this drag-and-drop area link here.

So I can go to the library to the zone equipment and I can select pieces of zone equipment and drop them on like this. You can then select them and inspect them. In this case I dropped a packaged terminal air-conditioner – we don't yet have a fancy view that lets you show the inside of these but you can inspect it here over on the right and see all of the components that make up that packaged terminal air-conditioner. In this case this one has a link to a plant loop and it lets you select them just like we did with the water coils.

So that's one kind of zone equipment. SystemOutliner also has a package terminal heat pump that you can drag onto the equipment and you can mix and match them; you can mix and match your HVA – your air loop systems and your zone equipment.

So at this point your model would be done from an HVAC point of view. And you could go back over them again to flush out the geometry and to actually run a simulation.

So that is the second demo that I wanted to share with you guys and that is how to customize your HVAC with SystemOutliner.

So if we pop back over to my slides the next thing I want to show you is the capability of SystemOutliner to take an existing idea and open it up and visualize it. And if you've used EnergyPlus in the past you know that opening up or looking at an existing idea up-file in raw text and the format that EnergyPlus uses natively, that's very challenging. You don't have a way of understanding how things are related to one another, so SystemOutliner helps with that.

So for that I'm going to start a new model again and discard the work that we just did and I'm going to click on the 'import' button down here. I'm going to navigate to one of the example files that come with the EnergyPlus engine itself. In this case I think we're going to open up the small-office reference building.

The first thing you'll often times see when you're importing existing ideas is that you'll get a prompt that says some portions of the IDF file were not imported. This is because OpenStudio has a file format that is separate from EnergyPlus's native file format. And when the reverse translator imports the existing IDF file there is something that it doesn't bring along, there are some things that the SystemOutliner doesn't yet understand. This dialogue is merely to tell you what things have been left out.

The good part about this design is that what does show up inside of SystemOutliner is complete and well-understood. So this is an opportunity for the OpenStudio to actually fix certain things that might be mismatched in your IDF file and eliminate inconsistencies in it. It also lets us gradually capture more and more features that EnergyPlus offers.

So in this case we imported the small-office reference building and you can see the schedules that are associated with that and you can see the thermal zones, and you can see the HVAC systems. In this case there's one packaged single-zone air-conditioning system for each one of the five zones that are in the model.

And you could start here and you could manipulate the HVAC systems. So we could take and remove the various air systems and then add our own back in. I can show you how that works. Here I'm just deleting the existing HVAC. I can go back to System 7 and I could add that, just like I showed you in the first demo.

So in a few clicks we took an existing model, ripped out all of the HVAC and then added a new HVAC system inside of it that is ready to simulate.

And speaking of simulations this might be a good time to go back over to Sketch-up and see the results of the simulation that we just did.

So you can see now that there's no local jobs running, there was no failed jobs and three jobs were complete. You might say, "Well, wait a minute, we only did one simulation." But inside of OpenStudio it actually broke up that one simulation into three separate jobs, so that's why you're seeing those three jobs completed.

But what we really care about are these output files here. These are standard EnergyPlus output files and the one that is most helpful is the HTML output. If I click on that it will open up my browser and it will show simulation results. And you can see that because we had cooling and heating we actually captured those end-uses that way.

In this case I didn't apply a space-type to my spaces, so I don't have interior lighting and exterior lighting and things like that but I could have easily added those things into the model as well inside the Sketch-up plug-in.

All right, so there is one more demonstration that I want to show everyone and then we'll talk about the future and areas where we can make SystemOutliner and the OpenStudio project better.

And this is a scripting demo. The purpose of this, in part, is to show you how you can use scripting to automate workflows, to make things that you do commonly, easy to do. There's actually another purpose to this and that is it gives me an opportunity to show everyone that OpenStudio, in part, is a software application that end-users can use.

But it is also a software API that software developers can use to make other applications. So, for example, if you're not happy with SystemOutliner being its own application and you have your own idea on how to make a different type of application, you could use the OpenStudio software API to build that application around and OpenStudio would do a lot of the hard work about connecting those together, about managing the HVAC system; essentially providing that drag-and-drop capability. There's a logic, at least, behind the drag-and-drop capability.

So for this part I'm going to start another new model. And I'm going to choose from the file menu 'show Ruby console.' So if you are a software programmer you might already know what the Ruby programming language is. If you're, not let me try to explain as quickly as I can. Ruby is essentially a scripting language that lets you – without having to compile a piece of software-type command. And what you're seeing here is an interactive Ruby console that lets you type commands and then apply those commands to the SystemOutliner interface and have the SystemOutliner interface respond to them.

Let me show you part of the Ruby interface that you can use to make things happen. The first think I'm going to do is add a thermal zone to the model, but instead of using the graphical interface I'm going to do that through Ruby. I'm going to type some commands – of this particular command added a new thermal zone and you can see that the SystemOutliner interface automatically updated in response to the commands that I just typed.

In this case I created a new thermal zone and added it to the OpenStudio model that SystemOutliner is showing you here. Now I have a zone – and you can see its name like this – and you can make changes to it.

In this case I'm going to tell the zone to use ideal air loads instead of complicated built-up HVAC. And again you can see that the interface responds to that.

Next I'm going to add one of the template HVAC systems. I do that like this. And this $M is just a global variable that represents the model that SystemOutliner is looking at the current point and time. So I'm just saying here that I want to add System-type 3 to the model. And when I do that SystemOutliner again responds showing you System-type 3.

In this case I forgot to hold onto that loop that represents System-type 3, so I'm going to use the API again to go back and get that loop. So I ask the model to get all of the air loop HVAC objects, and I only have one air loop so I'm going to ask for the first one.

Now you can see I have that air loop and I can add the zone that we already made to the air loop. So the point here is that I'm making these commands through the Ruby interfaces. These are the same things that are happening behind the scenes in the graphical user interface, it's just another way of getting at the same thing.

You could use all of this without having any of the UI involved at all. At this point it's partially a technology demonstration to who Ruby embedded inside of another application, but you can imagine how this could be used also to automate your workflows or it could be used even outside of the SystemOutliner all together.

There's just a couple more key parts of the API that I would like to show you. One is that you can ask the loop or all of its supply components, and I'll tell you that there's nine supply components on our air loop – those are these components on this side of the loop – and you can go and interact with them too.

I'm going to grab the second one – zero being the first one – and remove it. In this case that's our outdoor air system. And you can see, again, that simple API component made a lot of changes and managed the connections of the model automatically and for you. So I think that's quite a bit easier than working, for example at the EnergyPlus level, to make those things happen.

So with that, let me switch back over and talk about what we want to do with this in the future.

So the first thing – and this jumps out at you when you first start SystemOutliner – is we don't have a very interactive interface to define schedules. We have this nice, relatively easy-to-use HVAC interface that's drag-and-drop and you click on the 'schedule' tab – in fact it's the first tab that you see – and you see that it's pretty primitive on editing schedules. Well, we're planning on addressing that problem.

And this is a design spec for what we have in mind, and this is one of the first things that we hope to address in SystemOutliner and in OpenStudio in general. It's a nice easy-to-use interface like this to define the schedules which can define when HVAC systems are on, they could be used outside of HVAC for lighting and things like that too.

We're hoping that this one common interface can define schedules for all of those things. So this is certainly a near-term goal and it will be work that we do relatively soon.

The next one – and this is getting at work flow weakness of OpenStudio and SystemOutliner now – you notice I had to go back over to the Sketch-up plug-in to run the simulation. Well it turns out that that run manager interface is accessible for SystemOutliner so why not take that interface and drop it right inside of SystemOutliner so that the user can use it, and in fact we're planning on doing something just like that.

So this starts asking a more general question of why not have better integration with Sketch-up? I have no doubt that many people were thinking, if they're following along in the demonstration, that I started in Sketch-up, saved the model and then opened it up in SystemOutliner. Why do you have to go through that step?

So the OpenStudio team is right now thinking of solutions to that problem where we define the workflow entirely inside of one application so in the future we hope that you don't have to go back and forth between these different applications.

And kind of another part of that is there might be workflows where you don't need Sketch-up at all. Perhaps your intent is to experiment with a more advanced HVAC system and you only want simple representative geometry of your building. Perhaps you don't need a CAD tool at all to do that, perhaps you would just like to define a footprint and some basic geometric constraints on that footprint and have all of the spaces and thermal zones created for you.

So that's one thing that we're thinking about and I'm hoping maybe during the Q&A section that we might have some discussion about the importance of having that. We're kind of wondering is that a feature that is high on people's list or would people prefer rather to find all of their geometry inside of the Sketch-up plug-in alone?

Next up; we're working on a website and you can go to it right now, it's at and this is website that's serving as a repository for energy-modeling components; so these could be schedules, HVAC components, lights, you name it. If it's an energy model we're hoping that we can put it on the BCL website.

The one thought – and this is a screenshot of an experiment that we did – of taking the BCL website and putting it right inside of – in this case – SystemOutliner. And the intent here would be if we populate this website with a bunch of HVAC components you could kind of browse this thing like you browse the iTunes Store; click on a component that you want to download and then it would automatically be made to the SystemOutliner and the OpenStudio application as a whole.

We kind of think of it as going to iTunes and buying a song and then having it in your local library.

So the hope is that that addresses kind of populating that right-hand column of SystemOutliner – that library column – with a bunch of components, and maybe in the future components that users themselves upload to that library, to the BCL.

So with that, that is SystemOutliner. I hope that everybody found parts of SystemOutliner that they could find useful in their workflows and then also has ideas of how to make SystemOutliner better. And so hopefully it's during now – our question section – that we get at those topics.

A little bit of bookkeeping here. You can go to the OpenStudio website and get more details and download what I just demonstrated to you, and we also have quite a few user videos on YouTube at this link where you can actually see more workflows kind of like what I've showed you today.

Now I think Michelle's going to do some bookkeeping on how the Q&A's going to work.

Michelle Resnick:
Yep, thank you very much Kyle. Real quickly, before we get into Q&A we just want to get a sense for whether or not today's webinar covered what you were expecting today, and of course we can address those items that it didn't cover during the Q&A but I'm going to go ahead and put up a polling question, and I'd love to get people's answers here. So if you would so kind to let us know if this was covering what you were expecting and to also submit your questions through the Q&A pain at the top of your screen.

All right, thank you so much for voting. We're going to go ahead and get the Q&A kicked off. David, do you have a question you'd like to read?

David Goldwasser:
Sure. And actually before I jump into the first question – just to followup on Kyle's comments on where you can get information, everything he's been showing is actually in the 0.6 version of OpenStudio, which is due out later this month. So if you look on the OpenStudio website right now you'll see a 0.5 is all. If you come back later this month we'll have a 0.6, so you can wait until then if you want to download it or you could also go to our developer page and we do a release actually every two weeks and the latest release is very similar to what kind of product it will be, so I just wanted to kind of mention that before I forgot it.

So the first question we got was back when Kyle was working in Sketch-up originally setting up the model, and the question was "Did we specifically chose the thermostat in the Sketch-up environment," but – that loads to default? And it's asking do we have to choose thermostat or can you let the default get picked up?

So in Sketch-up we have spaces and so each space that Kyle made actually has the default space type associated with it – or can have a default space type associated with it, and that space type comes with the activities and the lows in the schedules that go along with the building activity.

Thermal zone can't be applied to a space because we might have multiple spaces in a single thermal zone, and if they have different thermostats those thermostats – we wouldn't know which thermostat to use for the thermal zone, so thermostats have to be applied at the thermal zone level as opposed to the space level.

Technically we probably could write it to default but at this point we've pre-loaded our templates for the thermostat appropriate for that building type and then you can apply those either one at a time or you can select all of them and globally select that thermostat.

Now Kyle opened the office template, so that only has the single thermostat for office, so if you opened up a more complex template like the large hotel, we have guest room thermostats and corridor thermostats and lobby thermostats and various ones, so you can make your own but we've tried to preload the building types with something to get you started.

Just to follow-up on that – it's kind of beyond the question – I said we can't put thermostats at this space level because we don't know what to do for thermal zone, yet we can do that for space loads. And the reason space loads isn't a problem is when we combine those we can do a weighted average and merge those space loads into the single thermal zone loads, so that just wasn't appropriate to do with thermostats.

For example, if one space was set to 65 and one was set for 70 you just don't want to combine those into a single zone that happens to be like 67.5.

Kyle, do you want to take the second question up there?

Kyle Benne:
Yeah, I see Michelle is kind of aggregating everyone's questions and she has quite a list, so I'll try to kind of rapid-fire through as many of them as I can.

Michelle Resnick:
You can read the next one that I've got. It was about you running the three jobs and asking if it broke up the simulation using three processors to speed up the runtime or was there another reason that it was broken into three pieces?

Kyle Benne:
This does not split up the energy simulation into three jobs running in parallel. The three jobs are merely there because it's running separate portions of the simulation in series to one another. So one part of that is converting the OpenStudio model into an EnergyPlus input file, another part of that is sometimes EnergyPlus input files have templates inside of them that need to be expanded, so that was another part of another job. And then the third job was actually running the HVAC – or the EnergyPlus simulation.

I should point out at this point that our run manager can support more than one simulation at a time and it can support running those in parallel. So, for example, if you had a model that you applied several permutations to that you were looking at wall insulation or HVAC alternative designs, if you saved those models individually and opened them up in the run manager application, which is part of Open Studio, you could run those in parallel. And in fact the run manager will actually work with other computers.

For example, the super computer that we have at NREL, and we'll fire jobs at that, so we can run hundreds of simulations in parallel with that tool – with the run manager tool.

All right, so the next question I see, "Can SystemOutliner create domestic and service hot water loops?" The short answer is no but the more complicated answer is that service water loops in OpenStudio are basically just another plant loop. So the only addition that we need to make, and we are in fact planning on making, is an end-use for domestic hot water. And so the longer answer is very shortly SystemOutliner will be able to cover that feature.

The one – the user is asking, "Are system layouts validated?" And this reminds me that I forgot to show a particular feature that I wanted to show surrounding this question. So, Michelle might be able to tell me if I can switch back to the desktop? I'll go ahead and do that I'll show you what we're doing to address the validation.

So back in SystemOutliner – let me start a new model for this. I'm going back on this because this was particularly important about how the OpenStudio software interface works.

If we add an empty air loop, like I did in the second demo, and I start dragging and dropping components onto that air loop the OpenStudio model validates in real-time what's going on.

So, for example, if I try to add another fan to the supply-side of an air loop that's not a valid EnergyPlus so SystemOutliner tells you right away that you can't do that. Likewise, if you try to drop a fan on the demand-side of the air loop, again, that's something that we can't do in EnergyPlus so it tells you that right away. The same with coils and things like that, they go on the supply-side, they don't go on the demand-side and SystemOutliner tells you that right away.

So I hope that addresses the question for the most part. I will say that there are situations where you could create something in SystemOutliner that is valid from OpenStudio's point of view but will not actually simulate.

For example, on this air loop that I just made here I haven't yet added any thermal loads, I haven't put any load on the demand side, so the simulation would still fail. But we do capture a lot of things before the simulation.

Okay, so the next one, "Is it possible to input cascading water loops, for example, during heat recovery?" Also, "Is it possible to attach heating and cooling equipment to the same loop? Is thermal storage implemented?"

Let me try to take these in series with one another. Cascading water loops are not possible yet, the most common example of this is a water-cooled chiller. But it is something that we have on our near-term horizon, and the interface will probably be similar to how we interact between a water coil on an air loop and a plant loop; that is you'll be able to select the loop interaction in the right column.

"Is it possible to attach heating and cooling equipment to the same loop?" I'm not sure I fully understand the question but I'll take a stab at it. For example, if you've got a DX cooling coil, you drop that onto a node, it belongs to one and only one air loop. If you've got a water coil it kind of sits between an air loop and a plant loop and if you add it to an air loop and then try to add it to two different plant loops it will disconnect that water coil from the existing plant and attach it to the new one, and then the interface will update to tell you that.

Unless – again, the short answer is no; however thermal storage can be modeled with EnergyPlus using another component and so it's relatively easy to add that feature, particularly if it's something that a lot of people want.

Next question; "How do you plan on adding HVAC systems and components, internally only or outsourcing?" I'm sure hoping that we can outsource some of it because it's a really big job.

David Goldwasser:
And if other people do make these the DCL's would be a good option to make those successful to additional users.

Kyle Benne:
There's kind of two levels there. The first level is does OpenStudio have that type of component? If it does then the job might merely be defining new parameters for an instance of that type. If the component doesn't exist in OpenStudio then the job might be a little bit bigger where we actually have to have somebody write the software to handle that component.

"How do you save a script?" You don't yet, at least not inside of SystemOutliner. There are some mechanisms to do that in the plug-in and if you go, for example, the OpenStudio YouTube channel you can see examples of that that David has put up there.

The hope is that in SystemOutliner we can demonstrate the technology at this point and we'll enable more features and make more use of that technology going forward.

Next question; "After changing the HVAC from the imported IDF file how do get back to a usable IDF file again given that some information was not retained?" This is something that we're working really hard on to make that import process better and more complete.

So in time the hope is that you will not lose really anything in the IDF file. In the short-term what I can tell you is that what we do import is understood and is complete. So we're not going to import part of your HVAC system and leave the rest of it just dangling out there with bad node connections and things like that.

We might, for example, drop an HVAC component out of that loop but the loops integrity won't completely be destroyed and you'll be able to see what's been dropped and then add things back in if you need to. But the best answer is long-term we're trying to get better and better coverage on that HVAC import.

You can in fact – there's a question, "Can we easily view and edit the node names?" You can do that; if you click on a node and then look at it in the inspector in the right-hand column it will show you that name and you can change it.

"Are other HVAC objects available currently that aren't in the templates; i.e. ERV, heat exchangers, chilled beams, geothermal exchangers, et cetera." The best example of that right now is evaporative cooling is in the library but that's the best outstanding example. We're trying to add more components as we go along and as fast as we can but we started with the Ashray Appendix-G types as our design requirements and we're going to move on from there going forward from this point.

Here's a question; "Does it handle EMF controls?" Short answer; it does not. We do have some cool UI ideas for that but in our list of priorities that one is a little bit lower. We might do some work around it to let you attach EMF's to the OpenStudio model as kind of a short-term solution to that. So I would say stay tuned on the EMF thing; we're aware of it and we're going to try to do something about it.

"What objects from EnergyPlus are you planning on implementing in OpenStudio next?" The very next thing that we're planning on doing is addressing the schedule user interface. From there, in terms of adding new HVAC components – to be honest, we haven't given it a great deal of thought yet but I'm certainly interested in what people want. So if you have a particular component that you're interested in send the OpenStudio an e-mail or request and you can send a request to my e-mail and we'll try to get it pushed up the list of things.

Here's a question; "What are typical memory requirements?" You know I've never actually looked at how much system memory SystemOutliner is using.

David Goldwasser:
I suspect that the largest memory point is probably Sketch-up if you have a lot of geometry models. So the memory required would depend on how complex your model might get.

Kyle Benne:
At this point I think it's safe to say that the computer resources are relatively low for the SystemOutliner application.

"When will a loop be available on the water side with a cooling tower only for cooling?" This – I'll have to admit – might actually be a candidate for one of the next types of components that we add, so I would answer that as fairly-shortly.

We have a question; "How many FTE's does the OpenStudio development team include? You are progressing so fast it's impressive." First, thanks for the compliment, we definitely work lots of overtime on this thing and people are really, really dedicated to the OpenStudio project here.

To answer the question I'll have to do a little inventory – David might help me here. David's saying about six; that sounds about right to me.

David Goldwasser:
We have a number of people dedicated 100 percent to this and then we have people who spend some time on it and some time on other work, so that's why we're trying to figure that out.

Kyle Benne:
The truth is that we don't have any one particular staff member that's 100 percent on OpenStudio. Almost every one of us as developers is working on a great deal of other things too, so we develop when we can and when we have program support for it.

There's a question; "When do you plan to support EnergyPlus 7?" The next release of OpenStudio that will be available in about week, I think –

David Goldwasser:
It's about December 15; I'm not sure on that exact date.

Kyle Benne:
That will be EnergyPlus 7. And in fact, what I showed you today is a pre-release so that is – the simulation that I ran today is EnergyPlus 7.

David Goldwasser:
Actually, on our download page are the major releases. On our developer page are the sub-releases – the duration releases – and 0.5.5 that's there now is actually EnergyPlus 7 compatible, so if you just downloaded EnergyPlus 7 you can use that OpenStudio to import IDFs and that went up just a day or two ago.

Kyle Benne:
We have another question; "Do you have to use Sketch-up or can you use system modeler with geometry generated with other software-stage design builder?" I think I'm going to let David take this one because he's really our resident architect and really understand the geometry well.

David Goldwasser:
So anything – both the Sketch-up plug-in part of OpenSystem as well as SystemOutliner can import IDF's. So really any application that can make an IDF can be used as a starting point into OpenStudio, so you could start in DesignBuilder, make and IDF and then import that into OpenStudio; however, because you're using and IDF as the import process it won't have spaces and space size, it will just have zones. So you won't be able to take full advantage of the software in all circumstances but you can certainly use it as a starting point.

Kyle Benne:
"Do we have a list of – prior type list of components to be delivered?" I think that's what we were looking for user input on.

David Goldwasser:
Yeah, I can take that one a little bit. We work on two-week iteration cycles where we do development for two weeks and then we release what we call an 'iteration build', so you can always see what we've done in the last two weeks.

We're closing up on an iteration and a major release, and so most of my time over the last few days has been not on development but on documentation. And one of the requests that I got to put in the documentation was just this; have a list of components – or even more particularly a list of the technologies that the tool supports, and then also including a list of what's planned on the horizon.

So based on the feedback from this webinar and from what people inside at NREL have been telling me, I'm going to be sure and include this kind of list in our next release with our documentation that you can get on or with a package for that matter, the download.

I'd add again that if you have requests I'm definitely interested in being responsive to those, so fire away.

Michelle Resnick:
And we did receive a few comments from people, so those we're collecting and we'll make sure that the team here has those for review; one about integration with Sketch-up and a couple of components, so we have those. If there's any questions we ask that folks submit them now.

All right, so I'm not seeing any additional questions but you do see the OpenStudio website up here and you can submit feedback on that and then Kyle's e-mail address is up there as well.

I would like to take a moment to thank everybody for attending our webinar for today and I wanted to let you all know that a copy of today's slide deck and video from today's webinar will actually be posted on the Commercial Building Energy Alliances website at and that's a mouthful. You can always go to and actually get to the link that will take you to the webinar archive page where all this information is going to be posted.

Thanks again to our speakers for their time today and to all of you for attending.

[End of Audio]